Revert "pthreadpool: split out pthreadpool_tevent_job from pthreadpool_tevent_job_state"
authorRalph Boehme <slow@samba.org>
Fri, 28 Dec 2018 08:03:45 +0000 (09:03 +0100)
committerStefan Metzmacher <metze@samba.org>
Fri, 11 Jan 2019 22:11:14 +0000 (23:11 +0100)
This reverts commit 245d684d28dab630f3d47ff61006a1fe3e5eeefa.

See the discussion in

https://lists.samba.org/archive/samba-technical/2018-December/131731.html

for the reasoning behind this revert.

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
lib/pthreadpool/pthreadpool_tevent.c

index 6999730..389bb06 100644 (file)
@@ -58,21 +58,15 @@ struct pthreadpool_tevent {
        struct pthreadpool *pool;
        struct pthreadpool_tevent_glue *glue_list;
 
-       struct pthreadpool_tevent_job *jobs;
+       struct pthreadpool_tevent_job_state *jobs;
 };
 
 struct pthreadpool_tevent_job_state {
-       struct tevent_context *ev;
-       struct tevent_req *req;
-       struct pthreadpool_tevent_job *job;
-};
-
-struct pthreadpool_tevent_job {
-       struct pthreadpool_tevent_job *prev, *next;
-
+       struct pthreadpool_tevent_job_state *prev, *next;
        struct pthreadpool_tevent *pool;
-       struct pthreadpool_tevent_job_state *state;
+       struct tevent_context *ev;
        struct tevent_immediate *im;
+       struct tevent_req *req;
 
        void (*fn)(void *private_data);
        void *private_data;
@@ -80,8 +74,6 @@ struct pthreadpool_tevent_job {
 
 static int pthreadpool_tevent_destructor(struct pthreadpool_tevent *pool);
 
-static void pthreadpool_tevent_job_orphan(struct pthreadpool_tevent_job *job);
-
 static int pthreadpool_tevent_job_signal(int jobid,
                                         void (*job_fn)(void *private_data),
                                         void *job_private_data,
@@ -131,8 +123,7 @@ size_t pthreadpool_tevent_queued_jobs(struct pthreadpool_tevent *pool)
 
 static int pthreadpool_tevent_destructor(struct pthreadpool_tevent *pool)
 {
-       struct pthreadpool_tevent_job *job = NULL;
-       struct pthreadpool_tevent_job *njob = NULL;
+       struct pthreadpool_tevent_job_state *state, *next;
        struct pthreadpool_tevent_glue *glue = NULL;
        int ret;
 
@@ -141,11 +132,10 @@ static int pthreadpool_tevent_destructor(struct pthreadpool_tevent *pool)
                return ret;
        }
 
-       for (job = pool->jobs; job != NULL; job = njob) {
-               njob = job->next;
-
-               /* The job this removes it from the list */
-               pthreadpool_tevent_job_orphan(job);
+       for (state = pool->jobs; state != NULL; state = next) {
+               next = state->next;
+               DLIST_REMOVE(pool->jobs, state);
+               state->pool = NULL;
        }
 
        /*
@@ -274,120 +264,27 @@ static void pthreadpool_tevent_job_done(struct tevent_context *ctx,
                                        struct tevent_immediate *im,
                                        void *private_data);
 
-static int pthreadpool_tevent_job_destructor(struct pthreadpool_tevent_job *job)
+static int pthreadpool_tevent_job_state_destructor(
+       struct pthreadpool_tevent_job_state *state)
 {
-       /*
-        * We should never be called with state->state != NULL.
-        * Only pthreadpool_tevent_job_orphan() will call TALLOC_FREE(job)
-        * after detaching from the request state and pool list.
-        */
-       if (job->state != NULL) {
-               abort();
-       }
-
-       /*
-        * If the job is not finished (job->im still there)
-        * and it's still attached to the pool,
-        * we try to cancel it (before it was starts)
-        */
-       if (job->im != NULL && job->pool != NULL) {
-               size_t num;
-
-               num = pthreadpool_cancel_job(job->pool->pool, 0,
-                                            pthreadpool_tevent_job_fn,
-                                            job);
-               if (num != 0) {
-                       /*
-                        * It was not too late to cancel the request.
-                        *
-                        * We can remove job->im, as it will never be used.
-                        */
-                       TALLOC_FREE(job->im);
-               }
-       }
-
-       /*
-        * pthreadpool_tevent_job_orphan() already removed
-        * it from pool->jobs. And we don't need try
-        * pthreadpool_cancel_job() again.
-        */
-       job->pool = NULL;
-
-       if (job->im != NULL) {
-               /*
-                * state->im still there means, we need to wait for the
-                * immediate event to be triggered or just leak the memory.
-                */
-               return -1;
-       }
-
-       return 0;
-}
-
-static void pthreadpool_tevent_job_orphan(struct pthreadpool_tevent_job *job)
-{
-       /*
-        * We're the only function that sets
-        * job->state = NULL;
-        */
-       if (job->state == NULL) {
-               abort();
+       if (state->pool == NULL) {
+               return 0;
        }
 
        /*
-        * We need to reparent to a long term context.
-        * And detach from the request state.
-        * Maybe the destructor will keep the memory
-        * and leak it for now.
+        * We should never be called with state->req == NULL,
+        * state->pool must be cleared before the 2nd talloc_free().
         */
-       (void)talloc_reparent(job->state, NULL, job);
-       job->state->job = NULL;
-       job->state = NULL;
-
-       /*
-        * job->pool will only be set to NULL
-        * in the first destructur run.
-        */
-       if (job->pool == NULL) {
+       if (state->req == NULL) {
                abort();
        }
 
-       /*
-        * Dettach it from the pool.
-        *
-        * The job might still be running,
-        * so we keep job->pool.
-        * The destructor will set it to NULL
-        * after trying pthreadpool_cancel_job()
-        */
-       DLIST_REMOVE(job->pool->jobs, job);
-
-       TALLOC_FREE(job);
-}
-
-static void pthreadpool_tevent_job_cleanup(struct tevent_req *req,
-                                          enum tevent_req_state req_state)
-{
-       struct pthreadpool_tevent_job_state *state =
-               tevent_req_data(req,
-               struct pthreadpool_tevent_job_state);
-
-       if (state->job == NULL) {
-               /*
-                * The job request is not scheduled in the pool
-                * yet or anymore.
-                */
-               return;
-       }
-
        /*
         * We need to reparent to a long term context.
-        * Maybe the destructor will keep the memory
-        * and leak it for now.
         */
-       pthreadpool_tevent_job_orphan(state->job);
-       state->job = NULL; /* not needed but looks better */
-       return;
+       (void)talloc_reparent(state->req, NULL, state);
+       state->req = NULL;
+       return -1;
 }
 
 struct tevent_req *pthreadpool_tevent_job_send(
@@ -395,9 +292,8 @@ struct tevent_req *pthreadpool_tevent_job_send(
        struct pthreadpool_tevent *pool,
        void (*fn)(void *private_data), void *private_data)
 {
-       struct tevent_req *req = NULL;
-       struct pthreadpool_tevent_job_state *state = NULL;
-       struct pthreadpool_tevent_job *job = NULL;
+       struct tevent_req *req;
+       struct pthreadpool_tevent_job_state *state;
        int ret;
 
        req = tevent_req_create(mem_ctx, &state,
@@ -405,10 +301,11 @@ struct tevent_req *pthreadpool_tevent_job_send(
        if (req == NULL) {
                return NULL;
        }
+       state->pool = pool;
        state->ev = ev;
        state->req = req;
-
-       tevent_req_set_cleanup_fn(req, pthreadpool_tevent_job_cleanup);
+       state->fn = fn;
+       state->private_data = private_data;
 
        if (pool == NULL) {
                tevent_req_error(req, EINVAL);
@@ -419,44 +316,39 @@ struct tevent_req *pthreadpool_tevent_job_send(
                return tevent_req_post(req, ev);
        }
 
-       ret = pthreadpool_tevent_register_ev(pool, ev);
-       if (tevent_req_error(req, ret)) {
+       state->im = tevent_create_immediate(state);
+       if (tevent_req_nomem(state->im, req)) {
                return tevent_req_post(req, ev);
        }
 
-       job = talloc_zero(state, struct pthreadpool_tevent_job);
-       if (tevent_req_nomem(job, req)) {
-               return tevent_req_post(req, ev);
-       }
-       job->pool = pool;
-       job->fn = fn;
-       job->private_data = private_data;
-       job->im = tevent_create_immediate(state->job);
-       if (tevent_req_nomem(job->im, req)) {
+       ret = pthreadpool_tevent_register_ev(pool, ev);
+       if (tevent_req_error(req, ret)) {
                return tevent_req_post(req, ev);
        }
-       talloc_set_destructor(job, pthreadpool_tevent_job_destructor);
-       DLIST_ADD_END(job->pool->jobs, job);
-       job->state = state;
-       state->job = job;
 
-       ret = pthreadpool_add_job(job->pool->pool, 0,
+       ret = pthreadpool_add_job(pool->pool, 0,
                                  pthreadpool_tevent_job_fn,
-                                 job);
+                                 state);
        if (tevent_req_error(req, ret)) {
                return tevent_req_post(req, ev);
        }
 
+       /*
+        * Once the job is scheduled, we need to protect
+        * our memory.
+        */
+       talloc_set_destructor(state, pthreadpool_tevent_job_state_destructor);
+
+       DLIST_ADD_END(pool->jobs, state);
+
        return req;
 }
 
 static void pthreadpool_tevent_job_fn(void *private_data)
 {
-       struct pthreadpool_tevent_job *job =
-               talloc_get_type_abort(private_data,
-               struct pthreadpool_tevent_job);
-
-       job->fn(job->private_data);
+       struct pthreadpool_tevent_job_state *state = talloc_get_type_abort(
+               private_data, struct pthreadpool_tevent_job_state);
+       state->fn(state->private_data);
 }
 
 static int pthreadpool_tevent_job_signal(int jobid,
@@ -464,20 +356,18 @@ static int pthreadpool_tevent_job_signal(int jobid,
                                         void *job_private_data,
                                         void *private_data)
 {
-       struct pthreadpool_tevent_job *job =
-               talloc_get_type_abort(job_private_data,
-               struct pthreadpool_tevent_job);
-       struct pthreadpool_tevent_job_state *state = job->state;
+       struct pthreadpool_tevent_job_state *state = talloc_get_type_abort(
+               job_private_data, struct pthreadpool_tevent_job_state);
        struct tevent_threaded_context *tctx = NULL;
        struct pthreadpool_tevent_glue *g = NULL;
 
-       if (state == NULL) {
-               /* Request already gone */
+       if (state->pool == NULL) {
+               /* The pthreadpool_tevent is already gone */
                return 0;
        }
 
 #ifdef HAVE_PTHREAD
-       for (g = job->pool->glue_list; g != NULL; g = g->next) {
+       for (g = state->pool->glue_list; g != NULL; g = g->next) {
                if (g->ev == state->ev) {
                        tctx = g->tctx;
                        break;
@@ -491,14 +381,14 @@ static int pthreadpool_tevent_job_signal(int jobid,
 
        if (tctx != NULL) {
                /* with HAVE_PTHREAD */
-               tevent_threaded_schedule_immediate(tctx, job->im,
+               tevent_threaded_schedule_immediate(tctx, state->im,
                                                   pthreadpool_tevent_job_done,
-                                                  job);
+                                                  state);
        } else {
                /* without HAVE_PTHREAD */
-               tevent_schedule_immediate(job->im, state->ev,
+               tevent_schedule_immediate(state->im, state->ev,
                                          pthreadpool_tevent_job_done,
-                                         job);
+                                         state);
        }
 
        return 0;
@@ -508,23 +398,27 @@ static void pthreadpool_tevent_job_done(struct tevent_context *ctx,
                                        struct tevent_immediate *im,
                                        void *private_data)
 {
-       struct pthreadpool_tevent_job *job =
-               talloc_get_type_abort(private_data,
-               struct pthreadpool_tevent_job);
-       struct pthreadpool_tevent_job_state *state = job->state;
+       struct pthreadpool_tevent_job_state *state = talloc_get_type_abort(
+               private_data, struct pthreadpool_tevent_job_state);
 
-       TALLOC_FREE(job->im);
+       if (state->pool != NULL) {
+               DLIST_REMOVE(state->pool->jobs, state);
+               state->pool = NULL;
+       }
 
-       if (state == NULL) {
-               /* Request already gone */
-               TALLOC_FREE(job);
+       if (state->req == NULL) {
+               /*
+                * There was a talloc_free() state->req
+                * while the job was pending,
+                * which mean we're reparented on a longterm
+                * talloc context.
+                *
+                * We just cleanup here...
+                */
+               talloc_free(state);
                return;
        }
 
-       /*
-        * pthreadpool_tevent_job_cleanup()
-        * will destroy the job.
-        */
        tevent_req_done(state->req);
 }